1. Field of the Invention
The present invention relates to the field of digital message transmission and more specifically transmitting data over a hybrid, radio/wired network.
2. Description of Related Art
Wired networks, such as the `internet`, telephone or cable television networks are well adapted for transmitting messages long distances quickly, but the intended recipient must be connected to the wired network.
Radio pager, or repeater systems, provide mobility to a recipient, but have problems transmitting great distances. Radio transmission also tends to be a problem in areas, such as cities, having high rise buildings. The buildings tend to block radio transmissions and cause `shadowing`. A transmitter/receiver, `transceiver`, communicating with radiowave signals has to contend with these shadowing effects. This problem tends to be worse when at least one of the transceivers is a mobile unit. As the mobile unit moves into an area which experiences shadowing, the received signal is attenuated, has multi-path interference and may reduce the signal quality to a degree that the message may not be received at all.
One method of combating shadowing is to position repeaters having antennae dispersed around an area in which radio communication is desired. Antenna rental space has become increasingly more costly causing this method to become increasingly unattractive.
Cellular telephone systems provide both mobility to the intended recipient, and can transmit great distances, provided that there is a cellular base station nearby. Message transmission by cellular telephones, however, tends to be costly. Most of the cost is due to providing continuous and real-time communication. Large volumes of packet data, such as "datagrams", do not need to be received in real-time, and do not have to be continuously received, thereby making transmission by cellular telephone `overkill`.
Message transmission, in general, becomes very costly, slow and complex when the system is driven by a `master` controller which organizes the transceivers under its control. The control communication, between the `master` and its transceivers, not part of messages to be delivered, or `overhead`, adds to the communication traffic. The transceivers also wait idle until there it is their rum to send or receive messages. As more transceivers are added, and/or the message traffic increases, the `master` becomes overloaded and becomes the limiting factor in message transmission.
Currently there is a need for a simple and inexpensive method of `datagram` transmission which provides mobility to a recipient, which has the long-distance ability and speed of a wired network.